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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Copyright (C) IBM Corporation, 2005
5 * Jeff Muizelaar, 2006, 2007
6 * Pekka Paalanen, 2008 <pq@iki.fi>
7 *
8 * Derived from the read-mod example from relay-examples by Tom Zanussi.
9 */
10
11#define pr_fmt(fmt) "mmiotrace: " fmt
12
13#include <linux/moduleparam.h>
14#include <linux/debugfs.h>
15#include <linux/slab.h>
16#include <linux/uaccess.h>
17#include <linux/io.h>
18#include <linux/mmiotrace.h>
19#include <linux/pgtable.h>
20#include <asm/e820/api.h> /* for ISA_START_ADDRESS */
21#include <linux/atomic.h>
22#include <linux/percpu.h>
23#include <linux/cpu.h>
24
25#include "pf_in.h"
26
27struct trap_reason {
28 unsigned long addr;
29 unsigned long ip;
30 enum reason_type type;
31 int active_traces;
32};
33
34struct remap_trace {
35 struct list_head list;
36 struct kmmio_probe probe;
37 resource_size_t phys;
38 unsigned long id;
39};
40
41/* Accessed per-cpu. */
42static DEFINE_PER_CPU(struct trap_reason, pf_reason);
43static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
44
45static DEFINE_MUTEX(mmiotrace_mutex);
46static DEFINE_SPINLOCK(trace_lock);
47static atomic_t mmiotrace_enabled;
48static LIST_HEAD(trace_list); /* struct remap_trace */
49
50/*
51 * Locking in this file:
52 * - mmiotrace_mutex enforces enable/disable_mmiotrace() critical sections.
53 * - mmiotrace_enabled may be modified only when holding mmiotrace_mutex
54 * and trace_lock.
55 * - Routines depending on is_enabled() must take trace_lock.
56 * - trace_list users must hold trace_lock.
57 * - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed.
58 * - pre/post callbacks assume the effect of is_enabled() being true.
59 */
60
61/* module parameters */
62static unsigned long filter_offset;
63static bool nommiotrace;
64static bool trace_pc;
65
66module_param(filter_offset, ulong, 0);
67module_param(nommiotrace, bool, 0);
68module_param(trace_pc, bool, 0);
69
70MODULE_PARM_DESC(filter_offset, "Start address of traced mappings.");
71MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing.");
72MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions.");
73
74static bool is_enabled(void)
75{
76 return atomic_read(&mmiotrace_enabled);
77}
78
79static void print_pte(unsigned long address)
80{
81 unsigned int level;
82 pte_t *pte = lookup_address(address, &level);
83
84 if (!pte) {
85 pr_err("Error in %s: no pte for page 0x%08lx\n",
86 __func__, address);
87 return;
88 }
89
90 if (level == PG_LEVEL_2M) {
91 pr_emerg("4MB pages are not currently supported: 0x%08lx\n",
92 address);
93 BUG();
94 }
95 pr_info("pte for 0x%lx: 0x%llx 0x%llx\n",
96 address,
97 (unsigned long long)pte_val(*pte),
98 (unsigned long long)pte_val(*pte) & _PAGE_PRESENT);
99}
100
101/*
102 * For some reason the pre/post pairs have been called in an
103 * unmatched order. Report and die.
104 */
105static void die_kmmio_nesting_error(struct pt_regs *regs, unsigned long addr)
106{
107 const struct trap_reason *my_reason = &get_cpu_var(pf_reason);
108 pr_emerg("unexpected fault for address: 0x%08lx, last fault for address: 0x%08lx\n",
109 addr, my_reason->addr);
110 print_pte(addr);
111 pr_emerg("faulting IP is at %pS\n", (void *)regs->ip);
112 pr_emerg("last faulting IP was at %pS\n", (void *)my_reason->ip);
113#ifdef __i386__
114 pr_emerg("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
115 regs->ax, regs->bx, regs->cx, regs->dx);
116 pr_emerg("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
117 regs->si, regs->di, regs->bp, regs->sp);
118#else
119 pr_emerg("rax: %016lx rcx: %016lx rdx: %016lx\n",
120 regs->ax, regs->cx, regs->dx);
121 pr_emerg("rsi: %016lx rdi: %016lx rbp: %016lx rsp: %016lx\n",
122 regs->si, regs->di, regs->bp, regs->sp);
123#endif
124 put_cpu_var(pf_reason);
125 BUG();
126}
127
128static void pre(struct kmmio_probe *p, struct pt_regs *regs,
129 unsigned long addr)
130{
131 struct trap_reason *my_reason = &get_cpu_var(pf_reason);
132 struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
133 const unsigned long instptr = instruction_pointer(regs);
134 const enum reason_type type = get_ins_type(instptr);
135 struct remap_trace *trace = p->private;
136
137 /* it doesn't make sense to have more than one active trace per cpu */
138 if (my_reason->active_traces)
139 die_kmmio_nesting_error(regs, addr);
140 else
141 my_reason->active_traces++;
142
143 my_reason->type = type;
144 my_reason->addr = addr;
145 my_reason->ip = instptr;
146
147 my_trace->phys = addr - trace->probe.addr + trace->phys;
148 my_trace->map_id = trace->id;
149
150 /*
151 * Only record the program counter when requested.
152 * It may taint clean-room reverse engineering.
153 */
154 if (trace_pc)
155 my_trace->pc = instptr;
156 else
157 my_trace->pc = 0;
158
159 /*
160 * XXX: the timestamp recorded will be *after* the tracing has been
161 * done, not at the time we hit the instruction. SMP implications
162 * on event ordering?
163 */
164
165 switch (type) {
166 case REG_READ:
167 my_trace->opcode = MMIO_READ;
168 my_trace->width = get_ins_mem_width(instptr);
169 break;
170 case REG_WRITE:
171 my_trace->opcode = MMIO_WRITE;
172 my_trace->width = get_ins_mem_width(instptr);
173 my_trace->value = get_ins_reg_val(instptr, regs);
174 break;
175 case IMM_WRITE:
176 my_trace->opcode = MMIO_WRITE;
177 my_trace->width = get_ins_mem_width(instptr);
178 my_trace->value = get_ins_imm_val(instptr);
179 break;
180 default:
181 {
182 unsigned char *ip = (unsigned char *)instptr;
183 my_trace->opcode = MMIO_UNKNOWN_OP;
184 my_trace->width = 0;
185 my_trace->value = (*ip) << 16 | *(ip + 1) << 8 |
186 *(ip + 2);
187 }
188 }
189 put_cpu_var(cpu_trace);
190 put_cpu_var(pf_reason);
191}
192
193static void post(struct kmmio_probe *p, unsigned long condition,
194 struct pt_regs *regs)
195{
196 struct trap_reason *my_reason = &get_cpu_var(pf_reason);
197 struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
198
199 /* this should always return the active_trace count to 0 */
200 my_reason->active_traces--;
201 if (my_reason->active_traces) {
202 pr_emerg("unexpected post handler");
203 BUG();
204 }
205
206 switch (my_reason->type) {
207 case REG_READ:
208 my_trace->value = get_ins_reg_val(my_reason->ip, regs);
209 break;
210 default:
211 break;
212 }
213
214 mmio_trace_rw(my_trace);
215 put_cpu_var(cpu_trace);
216 put_cpu_var(pf_reason);
217}
218
219static void ioremap_trace_core(resource_size_t offset, unsigned long size,
220 void __iomem *addr)
221{
222 static atomic_t next_id;
223 struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
224 /* These are page-unaligned. */
225 struct mmiotrace_map map = {
226 .phys = offset,
227 .virt = (unsigned long)addr,
228 .len = size,
229 .opcode = MMIO_PROBE
230 };
231
232 if (!trace) {
233 pr_err("kmalloc failed in ioremap\n");
234 return;
235 }
236
237 *trace = (struct remap_trace) {
238 .probe = {
239 .addr = (unsigned long)addr,
240 .len = size,
241 .pre_handler = pre,
242 .post_handler = post,
243 .private = trace
244 },
245 .phys = offset,
246 .id = atomic_inc_return(&next_id)
247 };
248 map.map_id = trace->id;
249
250 spin_lock_irq(&trace_lock);
251 if (!is_enabled()) {
252 kfree(trace);
253 goto not_enabled;
254 }
255
256 mmio_trace_mapping(&map);
257 list_add_tail(&trace->list, &trace_list);
258 if (!nommiotrace)
259 register_kmmio_probe(&trace->probe);
260
261not_enabled:
262 spin_unlock_irq(&trace_lock);
263}
264
265void mmiotrace_ioremap(resource_size_t offset, unsigned long size,
266 void __iomem *addr)
267{
268 if (!is_enabled()) /* recheck and proper locking in *_core() */
269 return;
270
271 pr_debug("ioremap_*(0x%llx, 0x%lx) = %p\n",
272 (unsigned long long)offset, size, addr);
273 if ((filter_offset) && (offset != filter_offset))
274 return;
275 ioremap_trace_core(offset, size, addr);
276}
277
278static void iounmap_trace_core(volatile void __iomem *addr)
279{
280 struct mmiotrace_map map = {
281 .phys = 0,
282 .virt = (unsigned long)addr,
283 .len = 0,
284 .opcode = MMIO_UNPROBE
285 };
286 struct remap_trace *trace;
287 struct remap_trace *tmp;
288 struct remap_trace *found_trace = NULL;
289
290 pr_debug("Unmapping %p.\n", addr);
291
292 spin_lock_irq(&trace_lock);
293 if (!is_enabled())
294 goto not_enabled;
295
296 list_for_each_entry_safe(trace, tmp, &trace_list, list) {
297 if ((unsigned long)addr == trace->probe.addr) {
298 if (!nommiotrace)
299 unregister_kmmio_probe(&trace->probe);
300 list_del(&trace->list);
301 found_trace = trace;
302 break;
303 }
304 }
305 map.map_id = (found_trace) ? found_trace->id : -1;
306 mmio_trace_mapping(&map);
307
308not_enabled:
309 spin_unlock_irq(&trace_lock);
310 if (found_trace) {
311 synchronize_rcu(); /* unregister_kmmio_probe() requirement */
312 kfree(found_trace);
313 }
314}
315
316void mmiotrace_iounmap(volatile void __iomem *addr)
317{
318 might_sleep();
319 if (is_enabled()) /* recheck and proper locking in *_core() */
320 iounmap_trace_core(addr);
321}
322
323int mmiotrace_printk(const char *fmt, ...)
324{
325 int ret = 0;
326 va_list args;
327 unsigned long flags;
328 va_start(args, fmt);
329
330 spin_lock_irqsave(&trace_lock, flags);
331 if (is_enabled())
332 ret = mmio_trace_printk(fmt, args);
333 spin_unlock_irqrestore(&trace_lock, flags);
334
335 va_end(args);
336 return ret;
337}
338EXPORT_SYMBOL(mmiotrace_printk);
339
340static void clear_trace_list(void)
341{
342 struct remap_trace *trace;
343 struct remap_trace *tmp;
344
345 /*
346 * No locking required, because the caller ensures we are in a
347 * critical section via mutex, and is_enabled() is false,
348 * i.e. nothing can traverse or modify this list.
349 * Caller also ensures is_enabled() cannot change.
350 */
351 list_for_each_entry(trace, &trace_list, list) {
352 pr_notice("purging non-iounmapped trace @0x%08lx, size 0x%lx.\n",
353 trace->probe.addr, trace->probe.len);
354 if (!nommiotrace)
355 unregister_kmmio_probe(&trace->probe);
356 }
357 synchronize_rcu(); /* unregister_kmmio_probe() requirement */
358
359 list_for_each_entry_safe(trace, tmp, &trace_list, list) {
360 list_del(&trace->list);
361 kfree(trace);
362 }
363}
364
365#ifdef CONFIG_HOTPLUG_CPU
366static cpumask_var_t downed_cpus;
367
368static void enter_uniprocessor(void)
369{
370 int cpu;
371 int err;
372
373 if (!cpumask_available(downed_cpus) &&
374 !alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) {
375 pr_notice("Failed to allocate mask\n");
376 goto out;
377 }
378
379 cpus_read_lock();
380 cpumask_copy(downed_cpus, cpu_online_mask);
381 cpumask_clear_cpu(cpumask_first(cpu_online_mask), downed_cpus);
382 if (num_online_cpus() > 1)
383 pr_notice("Disabling non-boot CPUs...\n");
384 cpus_read_unlock();
385
386 for_each_cpu(cpu, downed_cpus) {
387 err = remove_cpu(cpu);
388 if (!err)
389 pr_info("CPU%d is down.\n", cpu);
390 else
391 pr_err("Error taking CPU%d down: %d\n", cpu, err);
392 }
393out:
394 if (num_online_cpus() > 1)
395 pr_warn("multiple CPUs still online, may miss events.\n");
396}
397
398static void leave_uniprocessor(void)
399{
400 int cpu;
401 int err;
402
403 if (!cpumask_available(downed_cpus) || cpumask_empty(downed_cpus))
404 return;
405 pr_notice("Re-enabling CPUs...\n");
406 for_each_cpu(cpu, downed_cpus) {
407 err = add_cpu(cpu);
408 if (!err)
409 pr_info("enabled CPU%d.\n", cpu);
410 else
411 pr_err("cannot re-enable CPU%d: %d\n", cpu, err);
412 }
413}
414
415#else /* !CONFIG_HOTPLUG_CPU */
416static void enter_uniprocessor(void)
417{
418 if (num_online_cpus() > 1)
419 pr_warn("multiple CPUs are online, may miss events. "
420 "Suggest booting with maxcpus=1 kernel argument.\n");
421}
422
423static void leave_uniprocessor(void)
424{
425}
426#endif
427
428void enable_mmiotrace(void)
429{
430 mutex_lock(&mmiotrace_mutex);
431 if (is_enabled())
432 goto out;
433
434 if (nommiotrace)
435 pr_info("MMIO tracing disabled.\n");
436 kmmio_init();
437 enter_uniprocessor();
438 spin_lock_irq(&trace_lock);
439 atomic_inc(&mmiotrace_enabled);
440 spin_unlock_irq(&trace_lock);
441 pr_info("enabled.\n");
442out:
443 mutex_unlock(&mmiotrace_mutex);
444}
445
446void disable_mmiotrace(void)
447{
448 mutex_lock(&mmiotrace_mutex);
449 if (!is_enabled())
450 goto out;
451
452 spin_lock_irq(&trace_lock);
453 atomic_dec(&mmiotrace_enabled);
454 BUG_ON(is_enabled());
455 spin_unlock_irq(&trace_lock);
456
457 clear_trace_list(); /* guarantees: no more kmmio callbacks */
458 leave_uniprocessor();
459 kmmio_cleanup();
460 pr_info("disabled.\n");
461out:
462 mutex_unlock(&mmiotrace_mutex);
463}
1/*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
11 *
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
15 *
16 * Copyright (C) IBM Corporation, 2005
17 * Jeff Muizelaar, 2006, 2007
18 * Pekka Paalanen, 2008 <pq@iki.fi>
19 *
20 * Derived from the read-mod example from relay-examples by Tom Zanussi.
21 */
22
23#define pr_fmt(fmt) "mmiotrace: " fmt
24
25#define DEBUG 1
26
27#include <linux/module.h>
28#include <linux/debugfs.h>
29#include <linux/slab.h>
30#include <linux/uaccess.h>
31#include <linux/io.h>
32#include <linux/kallsyms.h>
33#include <asm/pgtable.h>
34#include <linux/mmiotrace.h>
35#include <asm/e820.h> /* for ISA_START_ADDRESS */
36#include <linux/atomic.h>
37#include <linux/percpu.h>
38#include <linux/cpu.h>
39
40#include "pf_in.h"
41
42struct trap_reason {
43 unsigned long addr;
44 unsigned long ip;
45 enum reason_type type;
46 int active_traces;
47};
48
49struct remap_trace {
50 struct list_head list;
51 struct kmmio_probe probe;
52 resource_size_t phys;
53 unsigned long id;
54};
55
56/* Accessed per-cpu. */
57static DEFINE_PER_CPU(struct trap_reason, pf_reason);
58static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
59
60static DEFINE_MUTEX(mmiotrace_mutex);
61static DEFINE_SPINLOCK(trace_lock);
62static atomic_t mmiotrace_enabled;
63static LIST_HEAD(trace_list); /* struct remap_trace */
64
65/*
66 * Locking in this file:
67 * - mmiotrace_mutex enforces enable/disable_mmiotrace() critical sections.
68 * - mmiotrace_enabled may be modified only when holding mmiotrace_mutex
69 * and trace_lock.
70 * - Routines depending on is_enabled() must take trace_lock.
71 * - trace_list users must hold trace_lock.
72 * - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed.
73 * - pre/post callbacks assume the effect of is_enabled() being true.
74 */
75
76/* module parameters */
77static unsigned long filter_offset;
78static bool nommiotrace;
79static bool trace_pc;
80
81module_param(filter_offset, ulong, 0);
82module_param(nommiotrace, bool, 0);
83module_param(trace_pc, bool, 0);
84
85MODULE_PARM_DESC(filter_offset, "Start address of traced mappings.");
86MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing.");
87MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions.");
88
89static bool is_enabled(void)
90{
91 return atomic_read(&mmiotrace_enabled);
92}
93
94static void print_pte(unsigned long address)
95{
96 unsigned int level;
97 pte_t *pte = lookup_address(address, &level);
98
99 if (!pte) {
100 pr_err("Error in %s: no pte for page 0x%08lx\n",
101 __func__, address);
102 return;
103 }
104
105 if (level == PG_LEVEL_2M) {
106 pr_emerg("4MB pages are not currently supported: 0x%08lx\n",
107 address);
108 BUG();
109 }
110 pr_info("pte for 0x%lx: 0x%llx 0x%llx\n",
111 address,
112 (unsigned long long)pte_val(*pte),
113 (unsigned long long)pte_val(*pte) & _PAGE_PRESENT);
114}
115
116/*
117 * For some reason the pre/post pairs have been called in an
118 * unmatched order. Report and die.
119 */
120static void die_kmmio_nesting_error(struct pt_regs *regs, unsigned long addr)
121{
122 const struct trap_reason *my_reason = &get_cpu_var(pf_reason);
123 pr_emerg("unexpected fault for address: 0x%08lx, last fault for address: 0x%08lx\n",
124 addr, my_reason->addr);
125 print_pte(addr);
126 print_symbol(KERN_EMERG "faulting IP is at %s\n", regs->ip);
127 print_symbol(KERN_EMERG "last faulting IP was at %s\n", my_reason->ip);
128#ifdef __i386__
129 pr_emerg("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
130 regs->ax, regs->bx, regs->cx, regs->dx);
131 pr_emerg("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
132 regs->si, regs->di, regs->bp, regs->sp);
133#else
134 pr_emerg("rax: %016lx rcx: %016lx rdx: %016lx\n",
135 regs->ax, regs->cx, regs->dx);
136 pr_emerg("rsi: %016lx rdi: %016lx rbp: %016lx rsp: %016lx\n",
137 regs->si, regs->di, regs->bp, regs->sp);
138#endif
139 put_cpu_var(pf_reason);
140 BUG();
141}
142
143static void pre(struct kmmio_probe *p, struct pt_regs *regs,
144 unsigned long addr)
145{
146 struct trap_reason *my_reason = &get_cpu_var(pf_reason);
147 struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
148 const unsigned long instptr = instruction_pointer(regs);
149 const enum reason_type type = get_ins_type(instptr);
150 struct remap_trace *trace = p->private;
151
152 /* it doesn't make sense to have more than one active trace per cpu */
153 if (my_reason->active_traces)
154 die_kmmio_nesting_error(regs, addr);
155 else
156 my_reason->active_traces++;
157
158 my_reason->type = type;
159 my_reason->addr = addr;
160 my_reason->ip = instptr;
161
162 my_trace->phys = addr - trace->probe.addr + trace->phys;
163 my_trace->map_id = trace->id;
164
165 /*
166 * Only record the program counter when requested.
167 * It may taint clean-room reverse engineering.
168 */
169 if (trace_pc)
170 my_trace->pc = instptr;
171 else
172 my_trace->pc = 0;
173
174 /*
175 * XXX: the timestamp recorded will be *after* the tracing has been
176 * done, not at the time we hit the instruction. SMP implications
177 * on event ordering?
178 */
179
180 switch (type) {
181 case REG_READ:
182 my_trace->opcode = MMIO_READ;
183 my_trace->width = get_ins_mem_width(instptr);
184 break;
185 case REG_WRITE:
186 my_trace->opcode = MMIO_WRITE;
187 my_trace->width = get_ins_mem_width(instptr);
188 my_trace->value = get_ins_reg_val(instptr, regs);
189 break;
190 case IMM_WRITE:
191 my_trace->opcode = MMIO_WRITE;
192 my_trace->width = get_ins_mem_width(instptr);
193 my_trace->value = get_ins_imm_val(instptr);
194 break;
195 default:
196 {
197 unsigned char *ip = (unsigned char *)instptr;
198 my_trace->opcode = MMIO_UNKNOWN_OP;
199 my_trace->width = 0;
200 my_trace->value = (*ip) << 16 | *(ip + 1) << 8 |
201 *(ip + 2);
202 }
203 }
204 put_cpu_var(cpu_trace);
205 put_cpu_var(pf_reason);
206}
207
208static void post(struct kmmio_probe *p, unsigned long condition,
209 struct pt_regs *regs)
210{
211 struct trap_reason *my_reason = &get_cpu_var(pf_reason);
212 struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
213
214 /* this should always return the active_trace count to 0 */
215 my_reason->active_traces--;
216 if (my_reason->active_traces) {
217 pr_emerg("unexpected post handler");
218 BUG();
219 }
220
221 switch (my_reason->type) {
222 case REG_READ:
223 my_trace->value = get_ins_reg_val(my_reason->ip, regs);
224 break;
225 default:
226 break;
227 }
228
229 mmio_trace_rw(my_trace);
230 put_cpu_var(cpu_trace);
231 put_cpu_var(pf_reason);
232}
233
234static void ioremap_trace_core(resource_size_t offset, unsigned long size,
235 void __iomem *addr)
236{
237 static atomic_t next_id;
238 struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
239 /* These are page-unaligned. */
240 struct mmiotrace_map map = {
241 .phys = offset,
242 .virt = (unsigned long)addr,
243 .len = size,
244 .opcode = MMIO_PROBE
245 };
246
247 if (!trace) {
248 pr_err("kmalloc failed in ioremap\n");
249 return;
250 }
251
252 *trace = (struct remap_trace) {
253 .probe = {
254 .addr = (unsigned long)addr,
255 .len = size,
256 .pre_handler = pre,
257 .post_handler = post,
258 .private = trace
259 },
260 .phys = offset,
261 .id = atomic_inc_return(&next_id)
262 };
263 map.map_id = trace->id;
264
265 spin_lock_irq(&trace_lock);
266 if (!is_enabled()) {
267 kfree(trace);
268 goto not_enabled;
269 }
270
271 mmio_trace_mapping(&map);
272 list_add_tail(&trace->list, &trace_list);
273 if (!nommiotrace)
274 register_kmmio_probe(&trace->probe);
275
276not_enabled:
277 spin_unlock_irq(&trace_lock);
278}
279
280void mmiotrace_ioremap(resource_size_t offset, unsigned long size,
281 void __iomem *addr)
282{
283 if (!is_enabled()) /* recheck and proper locking in *_core() */
284 return;
285
286 pr_debug("ioremap_*(0x%llx, 0x%lx) = %p\n",
287 (unsigned long long)offset, size, addr);
288 if ((filter_offset) && (offset != filter_offset))
289 return;
290 ioremap_trace_core(offset, size, addr);
291}
292
293static void iounmap_trace_core(volatile void __iomem *addr)
294{
295 struct mmiotrace_map map = {
296 .phys = 0,
297 .virt = (unsigned long)addr,
298 .len = 0,
299 .opcode = MMIO_UNPROBE
300 };
301 struct remap_trace *trace;
302 struct remap_trace *tmp;
303 struct remap_trace *found_trace = NULL;
304
305 pr_debug("Unmapping %p.\n", addr);
306
307 spin_lock_irq(&trace_lock);
308 if (!is_enabled())
309 goto not_enabled;
310
311 list_for_each_entry_safe(trace, tmp, &trace_list, list) {
312 if ((unsigned long)addr == trace->probe.addr) {
313 if (!nommiotrace)
314 unregister_kmmio_probe(&trace->probe);
315 list_del(&trace->list);
316 found_trace = trace;
317 break;
318 }
319 }
320 map.map_id = (found_trace) ? found_trace->id : -1;
321 mmio_trace_mapping(&map);
322
323not_enabled:
324 spin_unlock_irq(&trace_lock);
325 if (found_trace) {
326 synchronize_rcu(); /* unregister_kmmio_probe() requirement */
327 kfree(found_trace);
328 }
329}
330
331void mmiotrace_iounmap(volatile void __iomem *addr)
332{
333 might_sleep();
334 if (is_enabled()) /* recheck and proper locking in *_core() */
335 iounmap_trace_core(addr);
336}
337
338int mmiotrace_printk(const char *fmt, ...)
339{
340 int ret = 0;
341 va_list args;
342 unsigned long flags;
343 va_start(args, fmt);
344
345 spin_lock_irqsave(&trace_lock, flags);
346 if (is_enabled())
347 ret = mmio_trace_printk(fmt, args);
348 spin_unlock_irqrestore(&trace_lock, flags);
349
350 va_end(args);
351 return ret;
352}
353EXPORT_SYMBOL(mmiotrace_printk);
354
355static void clear_trace_list(void)
356{
357 struct remap_trace *trace;
358 struct remap_trace *tmp;
359
360 /*
361 * No locking required, because the caller ensures we are in a
362 * critical section via mutex, and is_enabled() is false,
363 * i.e. nothing can traverse or modify this list.
364 * Caller also ensures is_enabled() cannot change.
365 */
366 list_for_each_entry(trace, &trace_list, list) {
367 pr_notice("purging non-iounmapped trace @0x%08lx, size 0x%lx.\n",
368 trace->probe.addr, trace->probe.len);
369 if (!nommiotrace)
370 unregister_kmmio_probe(&trace->probe);
371 }
372 synchronize_rcu(); /* unregister_kmmio_probe() requirement */
373
374 list_for_each_entry_safe(trace, tmp, &trace_list, list) {
375 list_del(&trace->list);
376 kfree(trace);
377 }
378}
379
380#ifdef CONFIG_HOTPLUG_CPU
381static cpumask_var_t downed_cpus;
382
383static void enter_uniprocessor(void)
384{
385 int cpu;
386 int err;
387
388 if (downed_cpus == NULL &&
389 !alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) {
390 pr_notice("Failed to allocate mask\n");
391 goto out;
392 }
393
394 get_online_cpus();
395 cpumask_copy(downed_cpus, cpu_online_mask);
396 cpumask_clear_cpu(cpumask_first(cpu_online_mask), downed_cpus);
397 if (num_online_cpus() > 1)
398 pr_notice("Disabling non-boot CPUs...\n");
399 put_online_cpus();
400
401 for_each_cpu(cpu, downed_cpus) {
402 err = cpu_down(cpu);
403 if (!err)
404 pr_info("CPU%d is down.\n", cpu);
405 else
406 pr_err("Error taking CPU%d down: %d\n", cpu, err);
407 }
408out:
409 if (num_online_cpus() > 1)
410 pr_warning("multiple CPUs still online, may miss events.\n");
411}
412
413static void leave_uniprocessor(void)
414{
415 int cpu;
416 int err;
417
418 if (downed_cpus == NULL || cpumask_weight(downed_cpus) == 0)
419 return;
420 pr_notice("Re-enabling CPUs...\n");
421 for_each_cpu(cpu, downed_cpus) {
422 err = cpu_up(cpu);
423 if (!err)
424 pr_info("enabled CPU%d.\n", cpu);
425 else
426 pr_err("cannot re-enable CPU%d: %d\n", cpu, err);
427 }
428}
429
430#else /* !CONFIG_HOTPLUG_CPU */
431static void enter_uniprocessor(void)
432{
433 if (num_online_cpus() > 1)
434 pr_warning("multiple CPUs are online, may miss events. "
435 "Suggest booting with maxcpus=1 kernel argument.\n");
436}
437
438static void leave_uniprocessor(void)
439{
440}
441#endif
442
443void enable_mmiotrace(void)
444{
445 mutex_lock(&mmiotrace_mutex);
446 if (is_enabled())
447 goto out;
448
449 if (nommiotrace)
450 pr_info("MMIO tracing disabled.\n");
451 kmmio_init();
452 enter_uniprocessor();
453 spin_lock_irq(&trace_lock);
454 atomic_inc(&mmiotrace_enabled);
455 spin_unlock_irq(&trace_lock);
456 pr_info("enabled.\n");
457out:
458 mutex_unlock(&mmiotrace_mutex);
459}
460
461void disable_mmiotrace(void)
462{
463 mutex_lock(&mmiotrace_mutex);
464 if (!is_enabled())
465 goto out;
466
467 spin_lock_irq(&trace_lock);
468 atomic_dec(&mmiotrace_enabled);
469 BUG_ON(is_enabled());
470 spin_unlock_irq(&trace_lock);
471
472 clear_trace_list(); /* guarantees: no more kmmio callbacks */
473 leave_uniprocessor();
474 kmmio_cleanup();
475 pr_info("disabled.\n");
476out:
477 mutex_unlock(&mmiotrace_mutex);
478}